Ultra high frequency vibrator



April26, 1949. H. BENIOFF 2,463,538

ULTRA HIGH FREQUENCY VIBRATOR Filed Jan. 10, 1946 2 Sheets-Shet 1INVENTOR. HUGO BENIOFF April 26, 1949. H. BENIOFF 2,468,533

ULTRA HIGH FREQUENCY VIBRATOR Filed Jan. 10, 1946 I 2 Sheets-Sheet 2INVENTOR. HUGO BENIOFF HIS ATTORNEY Patented Apr. 26, 1949 UNITED1 STATEULTRA HIGH FREQUENCY VIBRATOR Hugo Benio'ff, Pasadena, Calif., assignor,by mesne assignments, to. Submarine Signal Company, Boston, Mass,acorporation of Delaware Application January 10, 1946, Serial No.640,249

10 Claims.

The present invention relates to an ultra high frequency vibrator of thetype disclosed in my copending application, Serial No. 606,498, filedJuly 23, 1945, and relates more particularly to improvements over theapparatus therein disclosed. One of the principal advantages inthepresent constructionis that. in the present device, the insulating oilsurrounding the oscillating element is sealed permanently rather thanbeing sealed by a removable seal like a packing glandor a.rubber gasket.The whole apparatus is placed under vacuum before filling to outgas thewhole structure. The oil is heated to 100C. under vacuum and their ispermitted to fill the chamber to full atmospheric pressure, thus entirely exhausting the oil of air and gas.

rials of liquids or solids which are placed in a container which fitsinto the top of the device in a liquid cup1ing.rnedium covering theelectrode of the crystal but separated from the insulating oil. Theapparatus may be used not only for laboratory work but also forindustrial and commercial purposes.

Further advantages and merits of the present invention will bemore'fully described in the specification below in connection with thedrawings showing an embodiment thereof, in which Fig. 1 shows a generalvertical sectional view through the apparatus taken on the line ll ofFig. 4; Fig. 2 shows a plan view as seen from the top of Fig. 1; Fig. 3shows a section taken on the line 33 of Fig. 1; and Fig. 4 shows a viewin vertical elevation of the device.

In the arrangement-illustrated by the figures the liquid vibrator, as awhole, is supported by a flange 9 on the inner side of which is attacheda flange 5 by means of a soft solder weld as indicated at 30. The collar5 is provided with an inwardly extending shoulder or'supporting ring 3|to which is attached a plate 32 by means of a series of screws 33clamping the plate 32 to the shoulder 3| between which is a sealinggasket l8. The plate 32 has attached 'on its under side a downwardlyextending cylindrical flange-or collar 34 to which is attached in turn aheat resistas will not crack underchanges in temperature.

fFirst a band of silver is fired o the ends of the means of soft solderof a suitable type.

ing glass tube 12 or such other type of glass tube 04' glass tube whichis then soldered by means of .roft' solder to' the collar 34 at the topand the collar 34' at *the'bottom. Fitting over the ends of the glasstube l2 are small. end fitting rings l0. and I0 which support the glasstube and to 'which'the collars 34' at the top and 34' at thebottom arealso soldered. The collar 34' at the base (Fig. 1) extends from thesupporting base 35 on which also the ring |0- is supported. Thesupporting base 35 is-formed with a cylindrical shell 36' which extendsupwardlyv and supports the quartz crystal 368.- The cylindrical shell.36 forming the chamber 36 is provided at the top with a narrow neckportion 31 and an end shoulder or corner 38 extending all the way aroundthe neck 31 serving as a seal for the crystal 368. The crystal isretained in the shoulder 38 by layer of silver is burned on the lowerface of the crystal which serves as the lower electrode 39 and a basefor soldering at the edge. The crystal 388 is formed of quartz or othersuitable piezoelectric mate-rial with electrode 39 on the bottom surfaceof the crystal and an electrode 40- which is a thin metallic diaphragmseparated from the top surface of the crystal by a thin oil film as willbe explained later. This thin diaphragm forms an acoustic windowwhereby'the vibrations are transmitted to the liquid chamber above it.The base member 35 mentioned previously is provided with air vents llextending from the outside of the device to the inside chamber 36. Abellows element 4| is attached to-the bottom of the base 35 by suitablemeans such as soldering and a communicating-passage 42 is providedthrough the base 35 to the'chamber formed with a glass tube I2 on theoutside and the cylindrical shell 36' on the inside which supports thepiezoelectric crystal. This chamber 43 and the inside of the bellows arefilled with insulating oil mentioned before which has been heated'andcooled under vacuum for sufficient time to withdraw all of the gasescontained in the oil. The oil of the chamber 43 surrounds the crystal363 on its sides and forms thev film on top of the crystal between thetop crystal surface and the metal electrode and dia phragm 40, The upperpart of the chamber 43 is separated from the liquid into which thesample to be vibrated is placed by the cylinder 44positioned'concentrically within the glass tube. The diaphragm 40 isattached by proper welding or otherwise to the bottom of the cylinder 44which is provided with a rounded flange on its base.

First a 'ratus.

3 The diaphragm 40 is preferably very thin so as to permit vibrations topass through it unimpeded and may be of Monel metal or some similar elegment. The tube 44 may be of copper and of comparatively thickerdimensions as this element need not enter into the vibrationandprovldesa path of high heat conductivity to carry heat away i from thecrystal. The top of the tube 44 restsin a shoulder in the plate 32 andhas also an upwardly extending cylindrical portion 45, by means of whicha seal is formed at the top of the chamber 43 with the downward flange49 of the ring 48. In this construction the sleeve or collar 2 welded tothe plate 32 is positioned concentrically with the various tubes andcylinders of the appa- The sleeve 2 is threaded at its top to receive acap 6 provided with an inwardly'exe tending flange and shoulder 41 onwhich the container orvessel 53 'is placed. The sleeve 2 is recessed atits inner top edge to form a seat for the flanged member 48 which iswelded to the sleeve 2. The member 48 has integrally formed with it theneck 49 abutting the collar 45.

Assembly is complete beiore the oil is introduced aotherwise the oilwould be exposed to air which would greatly increase its tendency towaves which would permit electrical breakdowns and decrease theefliciency of acoustic coupling.

I6 is a valve for evacuating and filling the chamber.

It should be noted that surrounding the quartz crystal 38B is a micaring3" which is supported by meansof three glass rods I! which lit inrecesses at the top in theiunder side of the plate 32 and at the bottomin the base 35. The length of the rods is such as to leavea smallspaceat thetop so as not to put pressure on the glass rods. Within thecylinder 44, which is closed at the bottom by the diaphragm 40 servingas an electrode for the quartz crystal 368, there is a liquidbath .52which serves as an acoustic or V vibratory coupling medium between thevibrations centrically positionedwith respect to said tube forming aportion of the inner wall of said chamher, said container having adiaphragm sealed to the bottom thereol.', said diaphragm extending overthe front surface of sald rystal with an oil film between. the .crystaland saidndiaphragm, meanseffecting a permanent seal atboth the bottomand top of said'chamber andinsulating oil substantially free of gasesextending throughout saidchamber. I

' 2; An ultra high frequency vibrator comprising a piezoelectriccrystal; having a thin peripheral flange. an enclosed cylinder having aseat formed.

around the. periphery atone end to which the flange of the crystalissealed, a heatreslstant insulating tube surrounding and concentric withsaid crystal and cylinderproviding the outer walls of an insulating oilchamber, a container concentrically positioned with respect tosaid tubeforming a portion of the'inner wall of said chamber, said containerhaving adiaphragrn sealed to the bottom thereof, said diaphragmextendingover the front surface of said crystal with an oil 3 film between. thecrystaland said diaphragm,

form bubbles under the action of intense sound means efiecting a.permanent seal at both the 7 bottom and top of said chamber andinsulating oil substantially free of gases extending throughout saidchamber and cooling means extending into said chamber. I v i 3. An ultrahigh frequency vibrator comprising a piezoelectric crystal having a thinperipheral r flange, an enclosedcylinder having a seat formed around.the periphery at one end to which the flange of the crystal is sealedby soft solder applied to burned on silver, a heat resistant in- Isulating tube surrounding and concentric with said crystal and cylinderproviding the outerwalls of an insulating oil chamber, a containerconcentrically positioned with respect to said; tube produced by thecrystal and the sample container 53 the bottom of which is immersed inthebath. The sample container 53 is seated in the holein the cap 6 andextends well down within the cylinder 44. The substance to be treated isplaced within the container 53 the bottom of which is covered with avery thin diaphragm 54. The sample may be a liquid or whatever isdesired to be treated with the vibrations produced b the device.

Electrical energy is conducted to the crystal in the manner similar tothat in my copending application mentioned above. The glass tube androds together with the liquid in the chamber 43 act as insulatingelements between the two electrodes 39 and 40. Electrical energy isconducted tothe electrode 39 through the'cylinder 36', the base 35 andthe outside protecting cover 55; The upperelectrode 40 is gro1mded tothe casing or supporting ring 8. The device is employed in the samemanner as described in my above mentioned said crystal and cylinderproviding the outer walls i of an insulating oil chamber, a containerconforming a portion of the inner wall of said chamber, said containerhaving a, diaphragm sealed to the bottom thereof, said diaphragmextending over the front surface of said crystal with an oil filmbetween the crystal and said diaphr'agm, means effecting a permanentseal at 1 both the bottom and top of said chamber comprising a thinflange extending upwardly from the top of said container, a collarconcentrically positioned with respect tosaid container and forming apermanent seal at the outer side of said chamber, said collar having aseating recess at the top thereof, a ring having a downwardly extendingflange positioned to adjoin the upwardly extending flange of saidcontainer. said ring being sealed in said seat and at the junction ofthe flange with the flange of the container.

4. An ultra high frequency vibrator comprising a piezoelectric quartzcrystal having a thin flange at its peripheral edge, a cylinder closedat one end and exposed to the air havinga thin section a at its openend, means sealing said crystal at its thin section to saidcylindenmeans providing a sealed chamber having its axis parallel withthe vibrational axis of said crystal and extending above and below thesame,coollng meansprovided atthe bottom of saidchamber, said chamberhaving an acousticwindow extending over the upper surface ofsaidgcrystal and means forming aliquid bath over said window and on theinner side of said chamber a mica insulating ring surrounding saidcrystal and positioned over saidflange, insulating, means supportingsaid ring within said'chamber.

5.An ultra high frequency vibrator comprising a piezoelectric crystalhaving a' relatively 6 P system, a second chamber outside of said sealedchamber and also having said diaphragm as a wall thereof, and anacoustic coupling medium window as anotherwall thereof, a substantiallygas-free insulating oil filling said chamber and thereby covering asurface of said crystal, said window being disposed to extend over saidsurface separated therefrom only by a film of said oil. v 6. An ultrahigh frequency vibrator comprising a hermetically sealed chamber havinga diaphragm as a wall member thereof, a substantially gas-freeinsulating oil filling said chamber, and

a piezoelectric crystal positioned in such 9101- imity to said diaphra mwall that said diaphragm wall may serve as onev electrode of a ystalvibrating system.

7. An ultra high frequency vibrator comprising a hermetically sealedchamber having a diaphragm as a wall member thereof, a substantiallygas-free insulating oil filling said chamber, a piezoelectric crystalpositioned in such proximity to said diaphragm wall that said diaphragmwall may serve as one electrode of a crystal vibrating system, a secondelectrode attached to a surface of said crystal, and means providingelectrical connections to said second electrode and to said diaphragm.

8. An ultra high frequency vibrator comprising ,a hermetically sealedchamber having a diaphragm as a wall member thereof, a substantiallygas-free insulating oil filling said chamber, a piezoelectric crystalpositioned in such proximity to said diaphragm wall that said diaphragmwall may serve as one electrode of a crystal vibrating in said secondchamber, whereby acoustic energy is coupled from said crystal to saidmedium through said diaphragm.

9. An ultra high frequency vibrator comprising a hermetically sealedchamber having a diaphragm as a wall member thereof, a'substantiallygas-free insulating oil filling said chamber, a

piezoelectric crystal positioned in such proximity to said diaphragmwall that said diaphragm wall may serve as one electrode of a crystalvibrating system, said chamber extending away from said diaphragmreentrantly as a cup with said diaphragm in the bottom thereof, and anacoustic coupling medium disposed in said 'cup;

10, An ultra high frequency vibrator comprising a hermetically sealedchamber having a diaphragm as avwall memberthereof, a substantiallygas-free insulating oil filling said chamber, a piezoelectric crystalpositioned in such proximity to said diaphragm wall that said diaphragmwall form of a bellows.

may serve as one electrode of a crystal vibrating system, a portion ofsaid chamber being in the HUGO BINIOI'P.

nnranancns crrl-m The following references are of record in the ilie ofthis patent:

UNITED STATES PATENTS

